Researchers have developed a way of freeze-drying eggs so that they can be kept at room temperature almost indefinitely in sealed sachets. To revitalise the eggs for use in fertility treatment, they then just add water.

The technique should make it easier and cheaper for women who want to store their eggs so they can undergo IVF treatment later in life or for women undergoing cancer treatment, which can leave them infertile.

Currently eggs are stored in liquid nitrogen at expensive facilities and can be left useless if allowed to defrost due to loss of power.

The freeze drying method has been developed by Dr Amir Arav, the founder of Israeli cryopreservation company Core Dynamics.

He said: “You can keep the powder at room temperature forever and just add water to bring it back to life.”

The company has used the process to freeze-dry 30 cow eggs, according to New Scientist magazine, which revealed details of the technique.

When the eggs were rehydrated, 23 of them were found to be still viable.

The next step for the company is to prove that rehydrated eggs can then be fertilised and grown into viable young. They then hope to try the method using human eggs.

The process works by collecting the eggs and soaking them in sugar-rich liquid that replaces the water inside. They are then rapidly frozen to -200C (-328f) in less than a second.

Any remaining water in the eggs is then removed in low pressure chambers leaving a powder that can then be stored in a vacuum sealed container or sachet.

Core Dynamics has already carried out freeze drying on other types of cells including human blood cells.

Dr Arav first reported their work with cows eggs at the Cryo conference for cryopreservation experts in Berlin, Germany, last month.

He said: "I believe the future of fertility preservation will be a simple 'on shelf' preservation."

Claus Andersen of the University Hospital of Copenhagen in Denmark, told New Scientist that there were still some hurdles to be overcome before the new technique could be used to help women wanting to store their eggs.

He said: “We need to know whether the oocytes (eggs) can be fertilised after freeze-drying, whether they form normal embryos and develop into healthy offspring.

“The freeze drying needs to be shown to be as good as the conventional method of freezing under liquid nitrogen and this could take some time.”